OF ARTS AND SCIENCES. 363 



specimens which I refer to this species were collected by E. Hall : one 

 in ponds at Athens, Illinois, the others on the Platte River, either 

 in Nebraska or Colorado ; but I have seen others from the Mississippi 

 Valley. They answer to Seubert's "forma intermedia" in the shape of 

 the leaves (except that they are not "remote crenulata") and in the 

 alternate flowers. Apparently the petals have not expanded. Search 

 should be made in drier ground for the terrestrial form ; which, in 

 Europe, has more numerous and opposite flowers with expanded red- 

 dish petals, " petala rubella." 



We have no specimens of the New Zealand and Australian species, 

 E. gratioloides, A. Cunn., which should belong to the above rather 

 than to the following species. 



2. E. Americana, Arn. This is the proper specific name for our 

 common species, not only because it is the PepUs Americana of Pursh, 

 but because Arnott's Elatine Americana was published in the year 

 1830, Fischer and Meyer's E. minima in 1836. This is the only 

 species we have on the Atlantic border, from New Hampshire to Vir- 

 ginia ; and we have it also from Colorado and from Oregon. It is not 

 rarely trimerous, especially the terrestrial form. Like E. triandra in 

 Europe, this also, when well developed in drier soil, has larger and 

 broader petals than in the figure by Sprague in Gray, Gen. 111. i. t. 95, 

 open in anthesis and remaining so, and tinged with rose-color or pur- 

 ple. A diminutive form of this state is E. Clintoniana, Peck in 2 2d 

 Report of Regents of the University of the State of N. Y., 1870, 

 p. 53 ; and this is the fiist indication in this country of the state in ques- 

 tion. Now that Mr. Peck has well-formed seeds of both forms, he is 

 convinced that his E. Clintoniana is merely a form of E. Americana. 

 The only other specimens we have of the open-flowered and com- 

 monly reddish-petalled E. Americana are large ones collected near 

 New Haven, Connecticut, in October, 1873, by Dr. F. W. Hall, and 

 communicated by Professor Eaton ; and a depressed state, from Mult- 

 nomah Co., Oregon, no. 134 of a collection made by T. "W. Howell, 

 and recently distributed by Mr. Woolson. In good fruits, the seeds 

 are rather more numerous than in the figure above referred to, rather 

 longer in proportion, and commonly more decidedly curved : in inser- 

 tion they are not so basal, yet all are ascending. 



3. E. BRACHYSPEUMA. Our Specimens are mostly terrestrial ; 

 and are from Illinois, E. Hall, Texas, E. Hall, 1872, uo. 37 of his 

 Texan distributed collection, and California, uo. 257 of Kellogg and 

 Harford's distributed collection ; the latter with expanded flowers. 

 A submersed or floating form, with narrower leaves, was collected by 



